Conventionally, the following processes is known as a process for producing an anti-form of an optically active β-hydroxy-α-aminocarboxylic acid ester by asymmetric reduction of a β-keto-α-aminocarboxylic acid ester.
(i) A process to synthesize an anti-form by asymmetrically hydrogenating a racemic β-keto-α-aminocarboxylic acid ester with catalytic asymmetric hydrogenation reaction using a ruthenium-optically active phosphine complex catalyst to syn-selectively synthesize an optically active β-hydroxy-α-aminocarboxylic acid ester; and inversing the steric configuration of the hydroxyl group at β-position in the obtained ester (Patent Document 1).
(ii) A process to anti-selectively synthesize an optically active β-hydroxy-α-aminocarboxylic acid ester by asymmetrically hydrogenating a β-keto-α-aminocarboxylic acid ester having no substituent group at the nitrogen atom with catalytic asymmetric hydrogenation reaction using a ruthenium-optically active phosphine complex catalyst (Patent Document 2).
(iii) A process to anti-selectively synthesize an optically active β-hydroxy-α-phthalimidocarboxylic acid ester by asymmetrically hydrogenating a racemic β-keto-α-phthalimidocarboxylic acid ester with catalytic asymmetric hydrogenation reaction using a ruthenium-optically active phosphine complex catalyst (Patent Document 3).
In addition, a β-keto-α-amino-higher carboxylic acid ester having a long carbon chain is an important synthesis intermediate of a ceramide derivative useful for skin protection agents among β-keto-α-aminocarboxylic acid esters. The following processes are conventionally known as processes for producing a β-keto-α-amino-higher carboxylic acid ester.
(iv) A process to obtain methyl β-keto-α-acetylaminooctadecanoate by homologation of palmitoyl chloride with methyl acetoacetate; and then, diazonizing the product by a phenyldiazonium salt; and reducing the diazo group with zinc (Patent Document 1).
(v) A method containing steps of oximating methyl β-keto-hexadecanoate with sodium nitrite; acetylating the hydroxyl group of the oxime; and successively reducing the oxime position by hydrogenation reaction (Patent Document 4).
Patent Document 1: JP 2976214 B
Patent Document 2: WO2005/005371
Patent Document 3: WO2005/069930
Patent Document 4: JP 2733583 B